PLATE 29 
Distribution of tissues (primary) in the potato: 
A. —Transverse section of part of the central cylinder and the cortex, showing 
small stem bundle, extent and position of external and internal phloem, proto- and 
meta-xylem, collenchyma and cortex, cambium, and pith. X94. 
B. —Transverse section through part of large stem bundle showing fascicular cam¬ 
bium and medullary rays. 
C. —Transverse section through a large stem bundle. X94. 
D. —Transverse section through somewhat older stem, showing interfascicular cam¬ 
bium and position of external phloem groups and endodermis. 
